Airfoil Trailing Edge Pedestal Flow Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In gas turbine engines, the increasing temperatures and heat loads in airfoils lead to challenges in cooling efficiency, particularly at the trailing edge cavity where the Mach number can exceed acceptable levels, and the availability of compressor bleed cooling air is decreasing, necessitating improved heat transfer and flow distribution solutions.
Innovation Solution
The implementation of a trailing edge cavity with a series of blocking, circular, and spear pedestals, each with specific geometries and spacings, that are integrally clocked and arranged radially to provide balanced flow restrictions and distribution, mimicking the effect of refractory metal cores with thinner sections for enhanced heat transfer and cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the area through which cooling air passes is increased to serve greater heat loads, then cooling capacity is improved, but the Mach number through the internal cavities increases causing deleterious effects
Solution Approach 1:
The trailing edge cavity is segmented into multiple flow passages by introducing sets of blocking pedestals, circular pedestals, and spear pedestals. This segmentation divides the cooling air flow into multiple smaller channels, allowing the cooling capacity to be increased while keeping the Mach number in each individual passage within acceptable limits.
2Loss of energy
If compressor bleed cooling air is reduced to improve fuel efficiency, then fuel efficiency is improved, but the heat transfer capability decreases
Solution Approach 1:
The pedestals are designed with specific geometric parameters including width-to-length ratios between 0.75 and 0.90, and controlled spacing between 0.025 and 0.100 inches. These parameter changes optimize the flow distribution and heat transfer characteristics, enabling effective cooling with reduced compressor bleed air.
Solution Approach 2:
Different pedestal geometries (blocking, circular, and spear shapes) are strategically positioned at different locations within the trailing edge cavity to create local flow control. This local quality variation optimizes heat transfer in specific high-heat-load areas while maintaining overall fuel efficiency.
3Temperature
If refractory metal cores with thinner sections are used to improve heat transfer, then conductive cooling is improved, but manufacturing complexity increases
Solution Approach 1:
Instead of using complex thin-section refractory metal cores, the patent uses ceramic cores with pedestal features that copy and replicate the flow distribution patterns of optimized designs. This approach achieves similar heat transfer performance through a manufacturable ceramic core geometry.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration maintains feed pressure, provides backflow margins for cooling holes, and enhances heat transfer, mitigating efficiency losses from increased flow, while reducing the need for thicker refractory metal cores, thus improving fuel efficiency and performance.
Implementation Method 1
at least one set of blocking pedestals located within the trailing edge cavity... provide balanced flow restrictions and distribution
Implementation Method 2
airfoils may be cast with an RMC (refractory metal core) trailing edge in order to provide augmented heat transfer simultaneously with improved performance by efficiently improving conductive cooling effects
Implementation Method 3
Complex internal cooling schemes may be configured to supply convective cooling and source film cooling
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
An airfoil (201) of a gas turbine engine includes an airfoil body (203) having a leading edge (212) and a trailing edge (214) extending in a radial direction, a trailing edge cavity (230) formed within the airfoil and proximate to the trailing edge of the airfoil, the trailing edge cavity extending from the trailing edge in a forward direction toward the leading edge, at least one set of blocking pedestals (240; 242) located within the trailing edge cavity, a set of circular pedestals (244) located aftward from the at least one blocking set of pedestals, and a set of spear pedestals (246) located aftward from the set of circular pedestals and closest to the trailing edge of the airfoil body. A corresponding core for manufacturing an airfoil is also provided.